{"id":31355,"date":"2022-10-11T14:18:37","date_gmt":"2022-10-11T12:18:37","guid":{"rendered":"https:\/\/karmaka.de\/?p=31355"},"modified":"2022-10-17T10:34:48","modified_gmt":"2022-10-17T08:34:48","slug":"early-differentiation-processes-on-mars-inferred-from-silicon-isotopes","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=31355","title":{"rendered":"Early differentiation processes on Mars inferred from silicon isotopes<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>Delphine Losno, Caroline Fitoussi, Bernard Bourdon<\/p>\n\n\n\n<p>Geochimica et Cosmochimica Acta<br>Available online 10 October 2022<\/p>\n\n\n\n<p><a href=\"https:\/\/www.sciencedirect.com\/science\/article\/pii\/S0016703722005324\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p>Update (17 October 2022): <a href=\"https:\/\/www.sciencedirect.com\/science\/article\/pii\/S0016703722005324\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>LINK<\/strong><\/a><br>Geochimica et Cosmochimica Acta<br>Volume 338, 1 December 2022, Pages 11-23<\/p>\n\n\n\n<p class=\"justify-text\">&#8220;Accretion of terrestrial planets involved partial or global melting events such as magma oceans or magma ponds. Mars experienced large-scale differentiation very early in its history, as shown by its 146Sm-142Nd and 182Hf-182W record. The broad variations in \u03b5142Nd and \u03b5142W of SNC meteorites highlight the presence of mantle sources that must have remained isolated, at least partly, after the crystallization of a global magma ocean. In this study, we have investigated whether the crystallization of the martian magma ocean could have generated mantle reservoirs characterized by different silicon isotope signatures, as the fractionation of Si isotopes between minerals and melts is known to depend on pressure. Thus, the goal of this study was to investigate whether there were any relationships between magma ocean crystallisation and possible variations in the Si isotope record of SNC meteorites. High resolution silicon isotope measurements were performed on twelve meteorites from the Shergottite, Nakhlite and Chassignite groups using a Neptune Plus MC-ICP-MS in dry plasma mode. The \u03b430Si values are in good agreement with previous studies but display a narrower range of variations with a mean value at -0.46 \u2030 \u00b1 0.07 (2SD). A magma ocean crystallization model shows that the range of \u03b430Si in SNCs is consistent with that generated by magma ocean crystallisation. In particular, there is a correlation between calculated 147Sm\/144Nd for the moderately depleted mantle sources with \u03b430Si values; this correlation is consistent with the crystallization model if one includes trapped melt in the cumulates. In contrast, enriched shergottites displayed a very homogenous composition in Sm\/Nd ratios, despite significant variability in \u03b430Si. This observation could be related to either fluid-rock interactions or redox effect during magma differentiation. Altogether, silicon isotope compositions of SNC provide new constraints about magma ocean crystallization processes in Mars.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Delphine Losno, Caroline Fitoussi, Bernard Bourdon Geochimica et Cosmochimica ActaAvailable online 10 October 2022 PDF (OPEN ACCESS) Update (17 October 2022): LINKGeochimica et Cosmochimica ActaVolume 338, 1 December 2022, Pages 11-23 &#8220;Accretion of terrestrial planets&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[45,75,122,42,44,73,43],"tags":[1963,6384,705,852,4098,1858,5400,2084,2192],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/31355"}],"collection":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=31355"}],"version-history":[{"count":3,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/31355\/revisions"}],"predecessor-version":[{"id":31376,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/31355\/revisions\/31376"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=31355"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=31355"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=31355"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}